The present invention relates to apparatus for providing a supply of labels and for transferring those labels to another location. In particular, the present invention relates to label transfer apparatus for picking up a label from a label supply means such as a magazine and transferring and depositing the label at a distal location, such as in the mold of a molding machine.
The present invention is also an improvement of the invention disclosed in application Ser. No. 544,986, now abandoned, by the same inventors, the application being incorporated herein by reference. That application also discusses the problems and disadvantages existing in the prior art label transferring apparatuses. However, those problems and disadvantages will be summarized herein for convenience.
It is known to apply a label to a plastic container that is made by blow molding by applying the label inside the mold. Previous arrangements for supplying the labels into the mold are depicted, for example, in the Dickinson U.S. Pat. No. 3,324,508, the Borkman U.S. Pat. No. 3,292,209, the two U.S. Hellmer U.S. Pat. Nos. 4,355,967 and 4,359,314, and the Hellmer et al U.S. Pat. No. 4,397,625. These references are discussed in the aforementioned patent application.
While the prior art does recognize the basic concept of supplying labels at one location and transferring those labels into an open mold at another location, the devices of the prior art suffer from certain disadvantages. Generally, the aforementioned patents disclose label transferring and applying machines having complex structures that are incapable of modification so as to permit their incorporation into conventional, installed mold machinery. Furthermore, the prior art devices do not permit very rapid, yet accurate transferring and positioning of the labels.
The successful, rapid and accurate positioning of a label inside the mold of a molding machine requires the interrelated, cooperative aspects of several components. Of particular importance is a transfer mechanism that is capable of positively and accurately removing a label from a label supply means, retaining the label during a transfer operation, and accurately, reliably depositing the label at the same location inside the mold. In addition, the transfer apparatus must have a reliable means for rapidly and accurately moving the transfer heads from a label supply means to the inside of a mold, and then retract to outside of the mold and return to the label supply means to continue the cycle.
The problems become even more difficult when the requirement is added that the label delivery apparatus must be designed with flexibility so that it can be incorporated into a number of different types of previously installed molding apparatuses. The requirement for component flexibility also means that the individual components must work separately and in combination in a variety of orientations and in a variety of machinery environments.
The critical interrelationships between the label pickup means and the label supplying means becomes even more important when high label transfer speed and accurate label positioning are required. Consistent accuracy can be achieved if the label transfer mechanism has a simplistic motion and it has to travel a minimal distance. In all of the devices of the aforementioned Dickinson, Borkman, Hellmer and Hellmer et al patents, there is a transverse component of movement between the transfer head and the label both at the moment of pickup of the label and at the moment of transfer of the label to the mold cavity. That transverse component of motion tends to "scuff" the label as it is being transferred, thereby possibly damaging the label and certainly minimizing the ability to perfectly position the label on the label transfer head and within the mold cavity. A simple motion of the transfer head is also dictated in order to permit the retrofitting of a label transfer mechanism to installed molding machines. Therefore, accuracy and speed of label transfer are increased with an increase in the simplicity of label pickup motion and distance of travel.
Hence, there exists a need for further improvements in apparatus for transferring labels from a label supply means to a mold such that the label can be accurately, yet rapidly transferred and positioned.